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The influence of colloidal parameters on the specific power absorption of PAA-coated magnetite nanoparticles.

Piñeiro-Redondo Y, Bañobre-López M, Pardiñas-Blanco I, Goya G, López-Quintela MA, Rivas J - Nanoscale Res Lett (2011)

Bottom Line: The understanding of the magnetic relaxation mechanism in biocompatible nanoparticle systems is crucial in order to optimize the magnetic properties and maximize the specific absorption rate (SAR).A remarkable decrease of the SAR values with increasing particle concentration and solvent viscosity was found.These behaviours have been discussed on the basis of the magnetic relaxation mechanisms involved.PACS: 80; 87; 87.85jf.

View Article: PubMed Central - HTML - PubMed

Affiliation: Applied Physics and Physical Chemistry Departments, University of Santiago de Compostela, Santiago de Compostela, 15782, Spain. manuel.banobre@usc.es.

ABSTRACT
The suitability of magnetic nanoparticles (MNPs) to act as heat nano-sources by application of an alternating magnetic field has recently been studied due to their promising applications in biomedicine. The understanding of the magnetic relaxation mechanism in biocompatible nanoparticle systems is crucial in order to optimize the magnetic properties and maximize the specific absorption rate (SAR). With this aim, the SAR of magnetic dispersions containing superparamagnetic magnetite nanoparticles bio-coated with polyacrylic acid of an average particle size of ≈10 nm has been evaluated separately by changing colloidal parameters such as the MNP concentration and the viscosity of the solvent. A remarkable decrease of the SAR values with increasing particle concentration and solvent viscosity was found. These behaviours have been discussed on the basis of the magnetic relaxation mechanisms involved.PACS: 80; 87; 87.85jf.

No MeSH data available.


Related in: MedlinePlus

Magnetization curves as a function of the applied magnetic field up to 2 T for Fe3O4@PAA NPs at room temperature.
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Figure 2: Magnetization curves as a function of the applied magnetic field up to 2 T for Fe3O4@PAA NPs at room temperature.

Mentions: Figure 2 shows the magnetization curves as a function of the applied magnetic field up to 2 T for PAA-coated magnetite NPs performed in a superconducting quantum interference device (SQUID) magnetometer. A clear SPM behaviour is observed where coercive forces and remanence are elusive. This is in good concordance with the XRD and TEM/STEM results which evidenced that magnetite cores are within the size region below the single- to multi-domain limit, in which FM particles show a SPM-like behaviour. Magnetization of saturation, Ms, is about 60 emu g-1 at room temperature. However, after correction of the magnetic data by subtracting the non-magnetic mass corresponding to the PAA shell (that represents a 25% of the total mass, as deduced from the thermal analysis), the saturation increases again until 80 emu g-1, which is very close to the bulk magnetization for magnetite (90 emu g-1). This indicates that the intrinsic magnetic properties of the magnetite nuclei have not been affected by the coating.


The influence of colloidal parameters on the specific power absorption of PAA-coated magnetite nanoparticles.

Piñeiro-Redondo Y, Bañobre-López M, Pardiñas-Blanco I, Goya G, López-Quintela MA, Rivas J - Nanoscale Res Lett (2011)

Magnetization curves as a function of the applied magnetic field up to 2 T for Fe3O4@PAA NPs at room temperature.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211476&req=5

Figure 2: Magnetization curves as a function of the applied magnetic field up to 2 T for Fe3O4@PAA NPs at room temperature.
Mentions: Figure 2 shows the magnetization curves as a function of the applied magnetic field up to 2 T for PAA-coated magnetite NPs performed in a superconducting quantum interference device (SQUID) magnetometer. A clear SPM behaviour is observed where coercive forces and remanence are elusive. This is in good concordance with the XRD and TEM/STEM results which evidenced that magnetite cores are within the size region below the single- to multi-domain limit, in which FM particles show a SPM-like behaviour. Magnetization of saturation, Ms, is about 60 emu g-1 at room temperature. However, after correction of the magnetic data by subtracting the non-magnetic mass corresponding to the PAA shell (that represents a 25% of the total mass, as deduced from the thermal analysis), the saturation increases again until 80 emu g-1, which is very close to the bulk magnetization for magnetite (90 emu g-1). This indicates that the intrinsic magnetic properties of the magnetite nuclei have not been affected by the coating.

Bottom Line: The understanding of the magnetic relaxation mechanism in biocompatible nanoparticle systems is crucial in order to optimize the magnetic properties and maximize the specific absorption rate (SAR).A remarkable decrease of the SAR values with increasing particle concentration and solvent viscosity was found.These behaviours have been discussed on the basis of the magnetic relaxation mechanisms involved.PACS: 80; 87; 87.85jf.

View Article: PubMed Central - HTML - PubMed

Affiliation: Applied Physics and Physical Chemistry Departments, University of Santiago de Compostela, Santiago de Compostela, 15782, Spain. manuel.banobre@usc.es.

ABSTRACT
The suitability of magnetic nanoparticles (MNPs) to act as heat nano-sources by application of an alternating magnetic field has recently been studied due to their promising applications in biomedicine. The understanding of the magnetic relaxation mechanism in biocompatible nanoparticle systems is crucial in order to optimize the magnetic properties and maximize the specific absorption rate (SAR). With this aim, the SAR of magnetic dispersions containing superparamagnetic magnetite nanoparticles bio-coated with polyacrylic acid of an average particle size of ≈10 nm has been evaluated separately by changing colloidal parameters such as the MNP concentration and the viscosity of the solvent. A remarkable decrease of the SAR values with increasing particle concentration and solvent viscosity was found. These behaviours have been discussed on the basis of the magnetic relaxation mechanisms involved.PACS: 80; 87; 87.85jf.

No MeSH data available.


Related in: MedlinePlus